Spherical-annular blowout preventer having a plurality of pistons

ABSTRACT

A blowout preventer includes a housing including interconnected cylinders formed therein, a main seal positioned within the housing, cylindrical sleeves removably placed within the interconnected cylinders, annular pistons and glands placed within the sleeves; and an energizing ring configured to be operated on by the annular pistons in order to operate the main seal. A blowout preventer may also include an upper gland assembly for isolating a void space within the housing from the interconnected cylinders.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part under 35 U.S.C. §120 of U.S.application Ser. No. 14/087,091, filed on Nov. 22, 2013, the entirety ofwhich is hereby incorporated by reference for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A COMPACT DISK APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The following description relates to blowout preventers used in the oiland gas industry during oil and gas well drilling and work over toprevent escape of well bore pressure into the outside environment in theevent of an unexpected pressure “kick” due to the influx of formationfluid or other uncontrolled situations. For example, anannular-spherical blowout preventer design may include multiple pistonsand glands.

2. Description of Related Art

Well control is an important aspect of oil and gas exploration. Forexample, when drilling a well, safety devices must be put in place toprevent damage to equipment and, most importantly, to personnelresulting from unexpected events associated with drilling operations.Because of safety conditions and risk of blowouts devices known asblowout preventers (BOPS) are installed above the wellhead at thesurface or on the sea floor in deep water situations to effectively seala wellbore until measures can be taken to control the kick. Blowoutpreventers are large, specialized high-pressure valves or similarmechanical devices, typically installed redundantly in stacks and usedto seal and control downhole pressure and monitor oil and gas wells toultimately prevent the uncontrolled flow of liquids and gases duringwell drilling operations. Blowout preventers come in a variety ofstyles, sizes and pressure ratings and often several individual unitsserving various functions are combined to compose a blowout preventerstack. Some of the functions of a blowout preventer system include, butare not limited to, confining well fluid to the wellbore, providing ameans to add fluid to the wellbore, allowing controlled volumes of fluidto be withdrawn from the wellbore, regulating and monitoring wellborepressure, and sealing the wellhead.

In addition to controlling the downhole pressure and the flow of oil andgas, blowout preventers are intended to prevent tubing, tools anddrilling fluid from being blown out of the wellbore when a blowoutthreatens. Blowout preventers are critical to the safety of crew, rigand environment, and to the monitoring and maintenance of wellintegrity. Thus, blowout preventers are intended to be fail-safedevices. Multiple blowout preventers of the same type are frequentlyprovided for redundancy, an important factor in the effectiveness offail-safe devices.

There are two major types of blowout preventers, annular and RAM.Annular BOPs are usually mounted to the very top of a BOP stack. Thedrilling crew then typically mounts a predetermined number of RAM BOPsbelow the annular blowout preventer. Blowout preventers were developedto cope with extreme erratic pressures and uncontrolled flow, oftenreferred to as formation kick, emanating from a well reservoir duringdrilling. Kicks can lead to a potentially catastrophic event known as a“blowout.” If a kick is detected, the annular is usually closed firstand then the RAM is used as a backup if the annular should fail. Oftentimes during operation BOPs are damaged and repair is difficult if notimpossible when dealing with internal component damage such as pistons.

In drilling a typical high-pressure well, drill strings are routedthrough a blowout preventer stack toward the reservoir of oil and gas.As the well is drilled, drilling fluid, “mud”, is fed through the drillstring down to the drill bit, “blade,” and returns up the wellbore inthe ring-shaped void, annulus, between the outside of the drill pipe andthe casing (piping that lines the wellbore). The column of drilling mudexerts downward hydrostatic pressure to counter opposing pressure fromthe formation being drilled, allowing drilling to proceed. When a kickoccurs, rig operators or automatic systems close the blowout preventerunits, sealing the annulus to stop the flow of fluids out of thewellbore. Denser mud is then circulated into the wellbore down the drillstring, up the annulus and out through the choke line at the base of theBOP stack through chokes until downhole pressure is overcome. If theblowout preventers and mud do not restrict the upward pressures of akick a blowout results, potentially shooting tubing, oil and gas up thewellbore, damaging the rig, and leaving well integrity in question.

SUMMARY OF THE INVENTION

According to an example, a blowout preventer includes an upper housingcomprising an inner ceiling with a cavity configured to accommodate amain seal, a lower housing comprising a plurality of internal fluidlyinterconnected cylinders, a plurality of annular pistons and glandsconfigured to be placed within the plurality of internal fluidlyinterconnected cylinders, an energizing ring configured to be operatedon by the annular pistons in order to operate the main seal, anddisposed circumferentially within a void area of the lower housing, andan upper gland assembly configured to isolate the plurality of internalfluidly interconnected cylinders from the void area of the lowerhousing.

In another example, a blowout preventer includes a housing comprising aplurality of fluidly interconnected cylinders formed therein, a mainseal positioned within the housing, a plurality of cylindrical sleevesremovably placed within the plurality of fluidly interconnectedcylinders, a plurality of annular pistons and glands configured to beplaced within the plurality of cylindrical sleeves, and an energizingring configured to be operated on by the annular pistons in order tooperate the main seal.

In another example, a piston cartridge configured to be used in ablowout preventer includes a cylindrical sleeve forming the outer wallof the piston cartridge, an annular piston placed within the cylindricalsleeve, and a gland retained on a distal portion of the pistoncartridge, wherein the annular piston comprises a hole configured toreceive a piston rod.

In another example, a method of using a blowout preventer includesproviding a piston cartridge, comprising a cylindrical sleeve, anannular piston, and a gland, into a cavity formed within the blowoutpreventer, connecting a piston rod of the blowout preventer to a holeformed within the annular piston of the piston cartridge; and coveringthe cavity of the blowout preventer using a bottom cover plate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description,will be better understood when read in conjunction with the appendeddrawings. For the purpose of illustration, certain embodiments of thepresent disclosure are shown in the drawings. It should be understood,however, that the invention is not limited to the precise arrangementsand instrumentalities shown. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustratean implementation of system, apparatuses, and methods consistent withthe present invention and, together with the description, serve toexplain advantages and principles consistent with the invention.

FIG. 1 illustrates a perspective view of an example of a blowoutpreventer assembly.

FIG. 2 illustrates a cross-sectional perspective view of the blowoutpreventer assembly connected according to one embodiment.

FIG. 3A illustrates a cross-sectional elevation view of the blowoutpreventer assembly rotated approximately 90 degrees from that as shownin FIG. 2, according to one embodiment.

FIG. 3B illustrates a cross-sectional elevation view of the blowoutpreventer assembly with Detail A of an annular piston and associatedgland indicated according to one embodiment.

FIG. 3C illustrates a magnified depiction of Detail A as shown in FIG.3B of a cross-sectional side view of the annular piston and glandaccording to one embodiment.

FIG. 4 illustrates a cross-sectional view of an energizing ring utilizedwith one embodiment of the blowout preventer.

FIG. 5 illustrates a cross-sectional view of a lower housing utilizedwith one embodiment of the blowout preventer.

FIG. 6 illustrates a cross-sectional view of an upper housing utilizedwith one embodiment of the blowout preventer.

FIG. 7 illustrates a cross-sectional view of another example of ablowout preventer assembly.

FIGS. 7A and 7B illustrate magnified depictions of an example of theblowout preventer including an adaptor ring with thru holes and a filteror wire mesh as shown in FIG. 7.

FIG. 8 illustrates a cross-sectional view of an example of a lowerhousing including an upper gland assembly and a cylindrical sleeve.

FIG. 9 illustrates a cross-sectional view of an example of the lowerhousing including an indicator/bleed port.

FIG. 9A illustrates a magnified depiction of an example of theindicator/bleed port as shown in FIG. 9.

FIG. 10 illustrates a cross-sectional view of an example of a removablepiston cartridge of the blowout preventer.

DETAILED DESCRIPTION OF THE INVENTION

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and to the arrangements of the componentsset forth in the following description or illustrated in the drawings.The Figures and written description are provided to teach any personskilled in the art to make and use the inventions for which patentprotection is sought. The invention is capable of other embodiments andof being practiced and carried out in various ways. Those skilled in theart will appreciate that not all features of a commercial embodiment areshown for the sake of clarity and understanding. Persons of skill in theart will also appreciate that the development of an actual commercialembodiments incorporating aspects of the present inventions will requirenumerous implementation specific decisions to achieve the inventors'ultimate goal for the commercial embodiment. While these efforts can becomplex and time-consuming, these efforts nevertheless would be aroutine undertaking for those of skill in the art having the benefit ofthis disclosure.

In addition, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting. For example, the use of a singular term, such as,“a” is not intended as limiting of the number of items. Also the use ofrelational terms, such as but not limited to, “top,” “bottom,” “left,”“right,” “upper,” “lower,” “down,” “up,” “side,” and “surface” are usedin the description for clarity in specific reference to the Figures andare not intended to limit the scope of the invention or the appendedclaims. Further, it should be understood that any one of the features ofthe invention can be used separately or in combination with otherfeatures. Other systems, methods, features, and advantages of theinvention will be or become apparent to one with skill in the art uponexamination of the Figures and the detailed description. It is intendedthat all such additional systems, methods, features, and advantages beincluded within this description, be within the scope of the presentinvention, and be protected by the accompanying claims.

Reference will now be made in detail to an implementation consistentwith the present invention as illustrated in the accompanying drawings.For the purpose of clarification, embodiments described herein referencethe term “fluid,” which refers to a gas, liquid, as well as liquidsolution with solid aggregates, as well as any other material that canreasonably be expected to flow.

Referring to FIG. 1, by way of non-limiting example, and consistent withembodiments of the invention, a blowout preventer assembly 1 is shown,wherein the blowout preventer assembly 1 is hydraulically actuated andis annular-spherical in overall design. When describing the operationalfunction of the present embodiment of the blowout preventer assembly 1,the volume of hydraulic fluid to effectuate desired operation is about 4gallons to “close” and about 3½ gallons to “open” a main seal 25 (seeFIGS. 2 and 3A) of the blowout preventer assembly 1. Further, in thepreferred embodiment, the inner dimensions of well pipe that can beaccommodated can range from about 5½ inches to about 21¼ inches. Allmetal components utilized in manufacture of the present embodiment, whenpossible and not restricted by pressure constraints or other operationalreasons, are manufactured and machined from commercially available 4130steel. One skilled in the art will recognize that other diameters, typesand thicknesses of steel or preferred materials can be utilized whentaking into consideration safety and the high pressure functioningcapacity of the present embodiment which can range in operation from3,000 psi to 20,000 psi.

The blowout preventer assembly 1 will now be discussed in detail withreference to the cross-sectional views as shown in FIGS. 2 and 3Atogether, wherein FIG. 3A is rotated clockwise in view about 90 degreesas compared to the view depicted in FIG. 2. The blowout preventerassembly 1 comprises a plurality of constituent components that provideblowout prevention in oil and gas well operation through implementationand operation of a plurality of annular pistons 40 (also shown inspecific detail in FIG. 3C), as will be further described. The blowoutpreventer assembly's 1 containment structure is generally configuredhaving a lower housing 10 with a plurality of internal fluidlyinterconnected cylinders 160, an upper housing 5 (also shown in specificdetail in FIG. 6), a one piece energizing ring 15 (also shown inspecific detail in FIG. 4), and a plurality of individual bottom coverplates 65. The blowout preventer assembly 1 also comprises acommercially available off-the-shelf main seal 25 with a plurality ofmain seal ribs 27, an adaptor ring 30, a plurality of glands 45 (alsoshown in specific detail in FIG. 3C) dedicated to each annular piston40, and various dedicated and associated seals and threaded attachmentswhich will be detailed hereinbelow with associated components. The mainseal is positioned over a bowl 155 machined into one end of theenergizing ring 15.

Referring to FIGS. 2, 3A and 6 together, the present embodiment of theblowout preventer assembly 1 comprises the upper housing 5 having aconcave inner design defining a spherical or concave shaped main bore 26in an inner ceiling 28 of the upper housing 5 that allows foraccommodation, fitment and operation of the main seal 25. The mainbore's 26 inner ceiling's 28 concave design provides circumferentialclosure guidance and integrity to bifurcations the main seal 25 whichfor the main seal ribs 27. The main seal ribs 27 function in conjunctionwith the inner ceiling 28 shape to cause sealing closure around andcontact with the outer diameter of pipe (not shown) positioned withinthe lower housing column bore 130 when demand for closure of the blowoutpreventer assembly 1 is required by induced well bore factors. The upperhousing 5 further comprises a series of spaced about female threadedconnections 9 for receiving upper housing bolts 8 used to provideattachment and securement of other desired gas or oil well/drillingcomponents. Further provided in an upper housing attachment end 4 of theupper housing 5 are a plurality of spaced apart individually machinedbifurcated upper housing retainer lugs 150 for secured attachment withthe lower housing 10 as will be described below. The bifurcated upperhousing retainer lugs 150 are positionally machined in a bifurcatedspaced apart protruding fashion about an outer circumference of an upperhousing attachment end 4, as shown in FIG. 6. The bifurcated upperhousing retainer lugs 150 operate to interlace, lock and secure, oncemated, the lower housing 10 with the upper housing 5 via a quarter turntwist, thus securing both together.

Referring to FIGS. 2, 3A, and 5 together, the present embodiment of theblowout preventer assembly 1 comprises the lower housing 10 having aunitary structure design that provides for and contains much of thefunctional components and machined portions of the overall blowoutpreventer assembly 1. Specifically, the unitary structure of the lowerhousing 10 defines a generally cylindrical shape having a lower housingflange 75, a plurality of machined bifurcated lower housing retainerlugs 145, a lower housing wall 167, a machined upper seat 6, a machinedupper shoulder 119, a lower seat 31, a lower housing column 164 having alower housing column wall 165 which defines an inner area of the lowerhousing column bore 130, lower housing column wall seals 166, and aplurality of internal fluidly interconnected cylinders 160 machined intoa cylinder plane surface 163 wherein each cylinder has a dedicatedcylinder fluid channel 161. Each of the previous mentioned componentsand its integral function will be further detailed hereinbelow.

An upper shoulder seal 120 and an adaptor ring upper seal 140 areutilized as mud and cutting scrapers and are designed to prevent ingressof mud and cuttings into a plurality of column primary seals 122 andinto a plurality of primary seals 95 and as a result prolongs theoverall life of each. The upper shoulder seal 120 is removably attachedto and circumferentially rests around and on the surface of an uppershoulder 119 via a plurality of upper shoulder seal retaining bolts 105and is further secured into position via a retainer lip 118 on theenergizing ring 15. An adaptor ring 30, having a plurality of adaptorring primary seals 95 and a plurality of adaptor ring secondary seals100, is removably disposed on a lower seat 31 around the outer diameterof the adaptor ring 30 and covering the area adjacent to the adaptorring upper seal 140 and the adaptor ring primary seal 95 to preventexternal escape of pressure built up in the blowout preventer assembly1.

The lower housing 10 mates for operation with the upper housing 5 andthe bifurcated upper housing retainer lugs 150 in a rotatable lockingattachment fashion via a plurality of spaced apart and machinedbifurcated lower housing retainer lugs 145 similar to those machinedinto the upper housing 5 described above. The plurality of bifurcatedlower housing retainer lugs 145, however, are postionally machined in abifurcated spaced apart protruding fashion about an inner circumferenceof a lower housing attachment end 11, as shown in FIG. 5. The bifurcatedlower housing retainer lugs 145 function to interlace, lock and secure,the lower housing 10 with the upper housing 5 via a quarter turn twistonce mated together and the upper housing 5 is properly seated on theupper seat 6 of the lower housing 10. The bifurcated upper housingretainer lug 150 and bifurcated lower housing retainer lug 145connection design also allows rapid disassembly and assembly in-houseand in the field.

The present embodiment of the lower housing 10, as shown in FIGS. 2, 3Aand 5 permits flow supply of demanded hydraulic fluid into the pluralityof internal fluidly interconnected cylinders 160 through two primarysupply ports, either an open port 305 or close port 310. The close port310 supplies hydraulic pressure in the bottom or close side of eachannular piston 40 to activate the main seal 25. When the main seal 25 isactivated from hydraulic fluid pressure through the close port 310 theblowout preventer assembly 1 is closed and the well bore is isolated andthus prevents well bore pressure from migrating above the main seal 25.When the main seal 25 is activated from the open port 305, hydraulicfluid pressure is supplied into an open side of the annular piston 40.The open and close function will be further described below.

As shown with specific reference to FIG. 5, in a preferred embodiment,six (6) internal fluidly interconnected cylinders 160 are machined intothe steel body of the lower housing 10. Each internal fluidlyinterconnected cylinder 160 is machined bored into a cylinder planesurface 163 that is located in a radial area bounded by the lowerhousing wall 167 and the lower housing column wall 165. Each of theinternal fluidly interconnected cylinders 160 is substantially equallyspaced apart from adjacent cylinders. The fluid interconnectivity ofeach internal fluidly interconnected cylinders 160 within the lowerhousing 10 is achieved via implementation of the machined cylinder fluidchannel 161 disposed in a horizontal plane within a circumferentialportion of a cylinder wall 162 within each of the internal fluidlyinterconnected cylinders 160.

A gland 45 having a circumferential channel 86, as shown in FIGS. 2, 3A,and 3C, with a plurality of gland seals 85 is disposed in a distalportion of the internal fluidly interconnected cylinder 160, wherein thedistal portion of the internal fluidly interconnected cylinders 160diameter that surrounds the gland 45 is of a second diameter larger thanthe first inner diameter of the internal fluidly interconnected cylinder160 that encloses the annular piston 40. Such smaller inner diameterportion of the cylinder 160 that encloses the annular piston 40 servesas a stop lip 146 and prevents movement during operation, or otherwise,of the gland 45 into the internal fluidly interconnected cylinder 160portion enclosing the annular piston 40. During all operations the gland45 is removably fixed in a stationary position and attached to a bottomcover plate 65 with a half tap gland plug 60. The only time the gland 45is removed is for repair or replacement of the annular piston 40 or thegland 45. The gland 45 can also be used as a secondary access to providehydraulic power into the annular piston 40. The gland 45 is the primarycomponent that provides for test access and isolation of the annularpistons 40.

As shown in FIGS. 3B and 3C an isolation and test plug 168 is providedfor conducting pressure testing on an individual internal fluidlyinterconnected cylinder 160 or an annular piston 40. The isolation andtest plug 168 can be used when inserted into the gland test plug cavity55 via an access aperture 115 to isolate an inoperable annular piston 40from all other annular pistons 40 within the blowout preventer assembly1, thereby preventing substantial downtime to drilling operations.During normal operations, the isolation and test plug 168 is removed andis not present and is replaced by the half tap gland plug 60 forcontinued operations. FIGS. 2 and 3C show the cross section of the gland45. The gland 45 has two longitudinal gland channels 50 traversing aninner portion of the gland 45. The gland channel 50 allows hydraulicfluid to flow to the annular piston 40 in the same internal fluidlyinterconnected cylinder 160 and allows hydraulic fluid to flow to thecylinder wall 162 and into the cylinder fluid channel 161, therebyproviding the aforementioned internal fluidly interconnected cylinder's160 interconnectivity. The bottom cover plates 65 are positioned in aplate channel 66 and are removably attached by a plurality of threadedfasteners, such as bottom cover plate bolts 70 into the lower housing 10to secure the glands 45 in place and to provide for easy access to theannular pistons 40 and the gland 45 for maintenance and/or removal.

The diameter and bore length of the internal fluidly interconnectedcylinders 160 are a predetermined factor and are based on of the overallsize and dimensions of the blowout preventer assembly 1 design which isdictated by operational necessity. Each annular piston 40 is fabricatedhaving an annular design of predetermined diameter to provide properfitment within the inner diameter of the internal fluidly interconnectedcylinder 160. The diameter and thickness of each annular piston 40 isdependent upon pressure requirements and other specifications of theoverall blowout preventer assembly 1 size and design. One skilled in theart will recognize the overall blowout preventer assembly 1 sizerequirements and the internal fluidly interconnected cylinder 160,annular pistons 40 and other herein described components and associatedsizing required can vary in size, length, diameter and type of steel forproper operation without departing from the scope and spirit of theinvention. The preferred embodiment can operate in the field to provideblowout prevention capability with fewer than six (6) functioningannular pistons 40 disposed in the internal fluidly interconnectedcylinders 160. However, blowout prevention is severely diminished orthreatened with three (3) or fewer operating internal fluidlyinterconnected cylinders 160 and/or annular pistons 40.

As shown in FIGS. 2, 3C and 4, the annular piston 40 is removablyattached to a surface of a heel 16 on the energizing ring 15 by way of apiston connector 90 for enabling operation of the blowout preventerassembly 1 to facilitate proper and sufficient component movement forultimate closure of the main seal ribs 27 of the main seal 25 around apipe (not shown) when positioned within the lower housing column bore130 and closure is demanded through a close port 310 due to hydraulicfluid operation. The annular pistons 40 have a plurality of sideperimeter grooves 81 for accommodating associated piston seals 80 toprevent pressurized fluid leakage into undesired portions of theinternal fluidly interconnected cylinder 160.

As shown in FIGS. 2 and 3A, the lower housing 10 and upper housing 5also enclose the energizing ring 15. The energizing ring 15 (detailed inFIG. 4) is disposed such that at least three of the heels 16, beingbifurcated in a equidistant and spaced apart fashion about a distal endof the energizing ring 15 can functionally engage at least three (3),preferably six (6), independent annular pistons 40, wherein the internalfluidly interconnected cylinders 160 and annular pistons 40 form ahoneycomb design within the lower housing 10. The energizing ring 15heels 16 are each separately connected to one side of the heels' 16accompanying annular pistons 40 via a piston connector 90 comprised of amale threaded bolt, seals and a nut. The piston connector 90 allowsremoval of either the annular piston 40 or the energizing ring 15.

Now, the close and open operation of the blowout preventer assembly 1will be described with reference to the Figures in general but withspecific reference to FIG. 3A. To close the blowout preventer assembly1, hydraulic fluid pressure is primarily supplied through the close port310. The hydraulic pressure provided exerts force on a piston close side169 to move the annular pistons 40 against the heel 16 of the energizingring 15. The force generated by the hydraulic pressure will then betransferred to the main seal 25 via the energizing ring 15. This willcause closure to the main bore 26 of the blowout preventer assembly 1thereby preventing all well bore pressure from escaping.

To open the blowout preventer assembly 1, hydraulic pressure isprimarily supplied through the open port 305. The hydraulic pressureprovided exerts force on a piston open side 170 to move the annularpistons 40 in a direction toward the gland 45. The force generated bythe hydraulic pressure will then be transferred to the energizing ring15 and will cause opening of the main seal 25 and as a result will openthe main bore 26 of the blowout preventer assembly 1.

FIG. 7 is a diagram illustrating another example of a blowout preventerassembly 2. The blowout preventer assembly 2 may include any of thecomponents of blowout preventer assembly 1 as described above, and mayoperate in the same way. For example, the blowout preventer assembly 2includes the upper housing 5, the lower housing 10, the main seal 25,the adaptor ring 30, the plurality of annular pistons 40 operatingwithin the plurality of internal fluidly interconnected cylinders 160formed in the lower housing 10, the plurality of glands 45 formed on thebottom of the fluidly interconnected cylinders 160, the bottom coverplates 65 covering the fluidly interconnected cylinders 160, among othercomponents of the blowout preventer assembly 1. Additionally, blowoutpreventer assembly 2 includes an open port 305 and close port 310 forthe supply of hydraulic fluid pressure to the annular pistons 40 and foroperating the main seal 25. A description of these components and theiroperations is provided in detail with reference to FIGS. 1-6 above.

Referring to the example shown in FIG. 7, the blowout preventer assembly2 includes an energizing ring 215 which may operates in a similar way asthe energizing ring 15 of the blowout preventer assembly 1. In thisexample, energizing ring 215 is placed within a void area 230 which isseparated from the fluidly interconnected cylinders 160 by an uppergland assembly 245. Accordingly, the upper gland assembly 245 isolatesand protects the fluidly interconnected cylinders 160 and componentstherein, such as the annular pistons 40 and the plurality of glands 45,from debris and well fluid which may enter the blowout preventer 2during drilling operations. For example, the upper gland assembly 245may include a plurality of upper gland assemblies 245 each being usedwith one of the plurality of fluidly interconnected cylinders 160, orthe upper gland assembly 245 may be one assembly wrapping around thecircumference of the blowout preventer 2 to isolate all fluidlyinterconnected cylinders 160. The energizing ring 215 is connected tothe annular pistons 40 by a piston rod 216, which will be described ingreater detail with reference to FIG. 8 below.

Still referring to FIG. 7, blowout preventer assembly 2 includes acylindrical sleeve 250 which is removably placed within the fluidlyinterconnected cylinder 160 of the lower housing 10. In this example,hydraulic fluid pressure drives the movement of the annular piston 40within the cylindrical sleeve 250, and a gland 45 is attached to thebottom of the cylindrical sleeve 250. The cylindrical sleeve 250 may beremoved entirely from the blowout preventer assembly 2 by removing thebottom cover plate 65. This will be described in greater detail withreference to FIG. 10 below.

In an aspect, a removable cylindrical sleeve 250 protects the walls ofthe fluidly interconnected cylinders 160 of the lower housing 10 fromcorrosion or damage, and provides a cheaper and faster process ofrefurbishing or reworking the lower housing 10. Further, the cylindricalsleeve 250 may be replaced with a new or refurbished cylindrical sleeve250 in a quick and easy replacement process. The cylindrical sleeve 250may be formed of any material, and is preferably formed of a lightweight, resilient, and non-corrosive material. For example, thecylindrical sleeve 250 may be formed of aluminum, Grade 410 StainlessSteel, or 17-4 PH Stainless Steel.

FIGS. 7A and 7B are diagrams illustrating magnified depictions of anexample of the blowout preventer assembly 2 including the adaptor ring30 having thru holes 280 and a filter or wire mesh 285. In this example,the adaptor ring 30 includes one or more thru holes 280, each of whichextends through the entire thickness of the adaptor ring 30. Any numberof thru holes 280 may be formed in any number of positions on theadaptor ring 30, and in a preferred example, eight thru holes 280 areformed in equally spaced positions around the circumference of theadaptor ring 30. Also, referring to FIG. 7B, a filter or wire mesh 285is formed in a slot within the upper circumference of the adaptor ring30 such that air may move freely between the void area 230 and the upperarea of the blowout preventer 2 which holds the main seal 25. In anexample, the thru holes 280 and the filter or wire mesh 285 of theadaptor ring 30 allow the void area 230 to breathe freely thuspreventing hydraulic lock which may result from pressure build-up withinthe void area 230, while the filter or wire mesh 285 protects the voidarea 230 from wellbore debris.

FIG. 8 is a diagram illustrating a cross-sectional view of an example ofthe lower housing 10 including the upper gland assembly 245 and thecylindrical sleeve 250. Referring to FIG. 8, the cylindrical sleeve 250includes the annular piston 40 operating therein and the gland 45attached at the bottom of the cylindrical sleeve 250. The gland 45includes the gland plug 60 and longitudinal gland channels 50 traversingan inner portion of the gland 45 for receiving hydraulic fluid pressureas described above.

Referring to FIG. 8, the annular piston 40 is connected to theenergizing ring 215 by a piston rod 216 which includes a shoulder bolt217 and a connector 218. The shoulder bolt 217 is connected to thebottom of the energizing ring 215, and the connector 218 is connected tothe annular piston 40 by projecting therethrough and connecting to acorresponding retainer 222 on the opposite side. In this example, theconnector 218 is threadedly engaged with the retainer 222. A face seal221 may be placed on the upper side of the annular piston 40 and aroundthe connector 218. Further, the upper gland assembly 245 includes aplurality of gland seals 85 within its outer and inner diameters forpreventing intrusion of wellbore fluid and debris. The upper glandassembly 245 includes a plurality of fastening holes 246 for receivingfasteners and securing the upper gland assembly 245 into the lowerhousing 10.

FIG. 9 is a diagram illustrating a cross-sectional view of an example ofthe lower housing 10 including an indicator/bleed port 290 andinterconnecting holes 251, and FIG. 9A is a diagram illustrating amagnified view of the indicator/bleed port 290. The indicator/bleed port290 may include an indicator 295 for determining conditions within thevoid area 230 such as pressure or temperature. In this example, theindicator 295 is a pressure indicator or bleed port for indicating to anoperator the pressure within the void area 230. Also, in an example, anoperator may access the void area 230 through the indicator/bleed port290 with a number of different tools.

FIG. 10 is a diagram illustrating a cross sectional view of the internalfluidly interconnected cylinders 160 and a removable piston cartridge200 in a nearly removed position. Referring to FIG. 10, the removablepiston cartridge 200 is a modular unit which includes the annular piston40 and the cylindrical sleeve 250. Also, the removable piston cartridge200 may include the gland 45 at the bottom of the cylindrical sleeve 250as shown in FIG. 8. The removable piston cartridge 200 may be sold andmanufactured separately or together with the blowout preventer assembly2. Also, each of the components of the removable piston cartridge 200,including the annular piston 40, the cylindrical sleeve 250, and gland45, may be sold and used as a modular unit together or separately.

The removable piston cartridge 200 may easily and quickly be removedfrom the fluidly interconnected cylinders 160 as a modular unit or inseparate components. For example, an operator or a machine may firstremove the bottom cover plate 65. The gland plug 60 of the gland 45 maythen be removed, and the gland 45 may subsequently be removed. Anoperator or machine may then loosen and remove retainer 222, as shown inFIG. 8, for detaching the connector 218 from the piston 40. The sleeve250 including the piston 40 may then be removed from the fluidlyinterconnected channel 160 as illustrated in FIG. 10. In anotherexample, each of the components, such as the cylindrical sleeve 250, theannular piston 40, and the gland 45 may be individually removed orreplaced without removing or replacing the entire piston cartridge 200as a modular unit.

Referring to FIGS. 9 and 10, the lower housing 10 includesinner-connection holes 251 which allow the interconnection of thefluidly interconnected cylinders 160, and the cylindrical sleeves 250include corresponding connection holes 252 which allow theinterconnection of the cylindrical sleeves 250. In this example, theuniform actuation of the main seal 25 is ensured through the equaldistribution of hydraulic fluid pressure formed between theinterconnected cylindrical sleeves 250. Accordingly, the operation ofthe annular piston 40 within the cylindrical sleeve 250 may be similarto the operations described above for the blowout preventer assembly 1.Hydraulic fluid pressure is introduced through an open port 305 forpushing down the annular piston 40 and opening the main seal 25, andhydraulic fluid pressure is introduced through a close port 310 forpushing up the annular piston 40 and closing the main seal 25.

It should be appreciated by one of ordinary skill in the art that thedimensions of the cylindrical sleeve 250 may vary, but the cylindricalsleeve 250 should be sized to fit within the fluidly interconnectedcylinders 160. In an example, an inner diameter of a fluidlyinterconnected cylinder 160 is 9.5 inches, the outer diameter of thecylindrical sleeve 250 is 9.48 inches, the inner diameter of thecylindrical sleeve 250 is 8.12 inches, and the height of the cylindricalsleeve 250 is 14 inches. Nevertheless, it should be appreciated that anumber of different dimensions may be used for any of the components ofthe blowout preventer assembly 1 and the blowout preventer assembly 2,and the dimensions described herein are not limiting.

One of skill in the art will recognize that the embodiments describedabove are not limited to any particular size and the size of the blowout preventer and will depend upon the particular application andintended components. It will be appreciated by those skilled in the artthat changes could be made to the embodiments described above withoutdeparting from the broad inventive concept thereof. It is understood,therefore, that the invention disclosed herein is not limited to theparticular embodiments disclosed, and is intended to cover modificationswithin the spirit and scope of the present invention.

What is claimed is:
 1. A blowout preventer, comprising: an upper housing comprising an inner ceiling with a cavity configured to accommodate a main seal; a lower housing comprising a plurality of internal fluidly interconnected cylinders; a plurality of annular pistons and glands configured to be placed within the plurality of internal fluidly interconnected cylinders; an energizing ring configured to be operated on by the annular pistons in order to operate the main seal, and disposed circumferentially within a void area of the lower housing; and an upper gland assembly configured to isolate the plurality of internal fluidly interconnected cylinders from the void area of the lower housing.
 2. The blowout preventer of claim 1, further comprising a plurality of cylindrical sleeves configured to be removably placed within the plurality of internal fluidly interconnected cylinders, each of the cylindrical sleeves configured to hold one of the plurality of annular pistons.
 3. The blowout preventer of claim 1, further comprising an adaptor ring positioned between the concave shaped cavity of the upper housing and the void area of the lower housing, the adaptor ring comprising a wire mesh surrounding a circumference of the adaptor ring and a thru-hole extending through a thickness of the adaptor ring.
 4. The blowout preventer of claim 1, further comprising an indicator port for determining a pressure level within the void area.
 5. The blowout preventer of claim 1, wherein the plurality of internal fluidly interconnected cylinders each comprises a dedicated cylinder fluid channel disposed within a portion therein, wherein the cylinder fluid channel permits hydraulic fluid interconnectivity of each of the plurality of internal fluidly interconnected cylinders.
 6. The blowout preventer of claim 2, wherein the plurality of internal fluidly interconnected cylinders each comprises a dedicated cylinder fluid channel disposed within a portion therein, and the plurality of cylindrical sleeves comprises one or more corresponding connecting holes disposed therein for permitting hydraulic fluid interconnectivity of each of the plurality of internal fluidly interconnected cylinders and each of the plurality of cylindrical sleeves.
 7. The blowout preventer of claim 1, wherein the lower housing comprises an open port and a close port for accommodating hydraulic connections for providing and relieving hydraulic fluid to cause the annular pistons to force the energizing ring in a direction to open or close the main seal.
 8. The blowout preventer of claim 7, wherein hydraulic fluid flows through the close port to the gland, wherein each gland further comprises a plurality of longitudinal gland channels traversing the diameter of the gland and a circumferential channel about the circumference of the gland, wherein each of the longitudinal gland channels and the circumferential channels combine in design and function to accommodate the hydraulic fluid flow to responsively effectuate movement of the piston and energizing ring in a direction to cause the seal to close.
 9. The blowout preventer assembly of claim 2, wherein each of the plurality of cylindrical sleeves has a first inner diameter for properly accommodating an outer diameter of each of the annular pistons and a second larger inner diameter for accommodating an outer diameter of each of the glands, such that the juncture of the first inner diameter and the second inner diameter form a stop lip.
 10. The blowout preventer assembly of claim 9, wherein each of the glands is positionally retained within a distal portion of each of the plurality of cylindrical sleeves by the stop lip.
 11. The blowout preventer assembly of claim 1, further comprising a piston rod for connecting the energizing ring to one of the plurality of annular pistons, wherein the upper gland assembly comprises a hole for receiving the piston rod.
 12. A blowout preventer, comprising: a housing comprising a plurality of fluidly interconnected cylinders formed therein; a main seal positioned within the housing; a plurality of cylindrical sleeves removably placed within the plurality of fluidly interconnected cylinders; a plurality of annular pistons and glands configured to be placed within the plurality of cylindrical sleeves; and an energizing ring configured to be operated on by the annular pistons in order to operate the main seal.
 13. The blowout preventer of claim 12, further comprising an upper gland assembly, wherein the energizing ring is disposed circumferentially within a void area of the housing, and the upper gland assembly is configured to isolate the plurality of internal fluidly interconnected cylinders from the void area of the lower housing.
 14. The blowout preventer of claim 12, wherein the housing comprises a plurality of connecting holes formed between the plurality of fluidly interconnected cylinders, and the plurality of cylindrical sleeves comprise a plurality of corresponding holes which correspond to the plurality of connecting holes, the plurality of connecting holes and the plurality of corresponding holes interacting together to provide fluid interconnectivity of all of the plurality of fluidly interconnected cylinders and all of the plurality of cylindrical sleeves.
 15. A piston cartridge configured to be used in a blowout preventer, comprising: a cylindrical sleeve forming the outer wall of the piston cartridge; an annular piston placed within the cylindrical sleeve; and a gland retained on a distal portion of the piston cartridge, wherein the annular piston comprises a hole configured to receive a piston rod.
 16. The piston cartridge of claim 15, further comprising connecting holes formed within the cylindrical sleeve for allowing the fluid interconnectivity of the piston cartridge with an internal environment of the blowout preventer.
 17. The piston cartridge of claim 15, further comprising a retainer for securing the annular piston to the piston rod, wherein in response to removing the retainer, the piston cartridge is detachable from the piston rod.
 18. A method of using a blowout preventer, comprising: providing a piston cartridge, comprising a cylindrical sleeve, an annular piston, and a gland, into a cavity formed within the blowout preventer; connecting a piston rod of the blowout preventer to a hole formed within the annular piston of the piston cartridge; and covering the cavity of the blowout preventer using a bottom cover plate.
 19. The method of claim 18, further comprising removing the piston cartridge, wherein the removing the piston cartridge comprises: removing the bottom cover plate; removing the gland; detaching a retainer holding the piston rod within the hole of the annular piston in order to detach the annular piston from the piston rod; simultaneously removing the cylindrical sleeve and the annular piston.
 20. The method of claim 19, wherein the removing of the piston cartridge is performed in order to replace or refurbish the piston cartridge, or in order to rework the cavity of the blowout preventer. 